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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
Editor in Chief :
Volume & Issues
Volume 21, Issue 6 - Dec 2007
Volume 21, Issue 5 - Oct 2007
Volume 21, Issue 4 - Aug 2007
Volume 21, Issue 3 - Jun 2007
Volume 21, Issue 2 - Apr 2007
Volume 21, Issue 1 - Feb 2007
Selecting the target year
Evaluation of Heat Balance for Cooling System of an Armored Installation in Small Space
Kim, Sung-Kwang ; Ahn, Seok-Hwan ; Nam, Ki-Woo ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 1~7
In this study, the heat balance test of an engine was conducted, and the heat released to coolant is measured and corrected using a power adjustment factor for high fuel temperature to simulate heat rejection of the engine. An engine-converter matching simulation program which can compute the engine speed, transmission output speed, transmission input and output power is developed from the vehicle, transmission and engine performance curve. With this information and the engine heat rejection characteristics, the engine and transmission heat rejection rates can be determined at given condition. In analyzing the air mass flow, a sub program computing the air mass flow rate from the equation of the pressure balance between cooling fan static pressure rise and pressure losses of cooling components is developed.
An Experimental Basic Study of Water Purification Function due to Spit in Small Estuary
Park, Sang-Kil ; Kim, Byung-Dal ; Jeong, Seong-Il ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 8~15
This study is intended to examine the relationship between the magnitude of sand spit in the estuary of the stream and improvement of the quality of water that flaws into the sea, by means of hydraulic experimentation. In order to determine the effect of improvements of water quality when river flow is stagnant, the estuary flows into the sea through the small sand spit, and a two-dimensional physical model experiment was carried out. Distribution of concentration was decreased in response to an increase in length of sand spit and time. The experimental results are compared with theoretical results, based on the solution of the equation. Also, there are functions of influx prevention of salt wedge and purification of pollution water due to sand spit in small estuary.
Comparative Study on Numerical Analysis Methods on the 2D Ground Effect
Kim, Yoon-Sik ; Shin, Myung-Soo ; Cho, Yong-Jin ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 16~25
A comparative study on the turbulent flaw simulation and the potential flaw analysis has been performed. A law Mach number preconditioned Navier-Stokes solver, using the multi-block grid method and a panel method based on the velocity potential, have been developed and validated by comparison to the experimental data. The present numerical analysis methods are applied to the ground effect problem around the NACA 4412 airfoil. It has been confirmed that the potential flaw analysis on the ground effect, using the image method, is consistent, to some degree, with the viscous calculations for high Reynolds number flows.
Large-Scale Experiments on the Wave-Induced Liquefaction of Sandbed
Kang, Yoon-Koo ; Suzuki, Kojiro ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 26~32
A series of large-scale experiments were carried out in order to examine wave-induced liquefaction in a loosely packed sandbed, its afterward high densification and liquefaction by oscillatory pore pressure. The experiments were conducted in a Large Hydro-Geo Flume that can nearly solve the problems of scale effects of the sandbed, and the 50% sieve diameter of sand was 0.2 mm. The generation of residual pore pressure and its afterward high densification which had observed by Takahashi et al. (1999) in a wave flume experiment using fine sand with the size of 0.08 mm. As a result, the relative density of the sandbed after high densification was increased up to 79% and liquefaction by oscillatory pore pressure was not observed.
Study on the Docking Algorithm for Underwater-Docking of an AUV Using Visual Guidance Device
Choi, Dong-Hyun ; Jun, Bong-Huan ; Lee, Pan-Mook ; Kim, Sang-Hyun ; Lim, Geun-Nam ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 33~39
The more deeply the researches make progress in ocean researches including the seabed resource investigation or the oceanic ecosystem investigation, the more important the role of UUV gets. In case of study on the deep sea, there are difficulties in telecommunications between AUV and ships, and in data communication and recharging. Therefore, docking is required. In AUV docking system, the AUV should identify the position of docking device and make contact with a certain point of docking device. MOERI (Maritime & Ocean Engineering Research Institute), KORDI has conducted the docking testing on AUV ISIMI in KORDI ocean engineering water tank. As AUV ISIMI approachs the docking device, there is some cases of showing an unstable attitude, because the lights which is on Image Frame are disappeared. So we propose the docking algorithm that is fixing the rudder and stem, if the lights on image frame are reaching the specific area in the Image Frame. Also we propose the new docking device, which has a variety of position and light number. In this paper, we intend to solve the some cases of showing an unstable attitude that were found in the testing, which, first, will be identified the validity via simulation.
Experimental Investigation For Various Propeller Tunnel Geometry Effect On Propulsion Performance
Suh, Sung-Bu ; Park, Choong-Hwan ; Moon, Il-Sung ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 40~45
This study was performed to investigate the effect of various propeller tunnel shapes on the propulsion performance of a fishing boat. The propeller tunnel reduces the problem resulting from the open propeller accidentally catching the waste net and cable on the sea, as well as increasing the cruising speed. For 3 different tunnel geometries, the model test is conducted in the circular water channel, and the potential based panel method was applied to analyze the hydrodynamic characteristics of propeller. Also, both results are compared with each other to represent the difference between results of the model scale test and the potential theory. It is expected that these results could be referenced in the design of the propeller tunnel in consideration of the hydrodynamic interaction between the propeller and the tunnel.
Hetero-core Spliced Fiber Optical Sensing System for an Environment Monitoring
Kim, Young-Bok ; Lee, Kwon-Soon ; Watanabe, Kazuhiro ; Sasaki, Hiroyuki ; Choi, Yong-Woon ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 46~51
A multi-purpose environmental monitoring system has been developed as a commercially available standard using the technique of hetero-core spliced fiber optic sensors, for the purposes of monitoring large-scale structures and preserving natural environments. The monitoring system has been tested and evaluated in a possible outdoor condition, in view of the full-scale operation at actual sites to be monitored. Additionally, the developed system in this work conveniently provides us with various options of sensor modules intended for monitoring such physical quantities as displacement, distortion, pressure, binary states, and liquid adhesion. Two channels of optical fiber line were monitored in each channel, three displacement sensor modules were connected in series, in order to examine the performance to a pseudo-cracking experiment in the outdoor situation and to clarify temperature influences an the system, in terms of the coupling of optical connectors and the OTDR stability. The results from the pseudo-cracking experiment agreed with the actual cracks, by means of calculation, based an the detected displacement values and their geometrical arrangement of the used sensor modules. The temperature change, ranging from 10 to
resulting from the 10-days free running operation, was found to influence the system stability of
, primarily due to the coupling instability of the used optical connectors. It was found that fusion splicing, rather than the use of connectors, reduced the fluctuation dawn to
. The specification and performance of various option modules have been demonstrated to show the capability of inspecting various physical quantities by use of the single system, which would be suitable for multi-purpose environmental monitoring.
Experimental Study on the Ultimate Strength of Composite Cylinders under Hydrostatic Pressure
Cho, Sang-Rai ; Koo, Jeong-Bon ; Cho, Jong-Rae ; Kwon, Jin-Hwe ; Choi, Jin-Ho ; Kim, Hyun-Su ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 52~57
Composite material is one of the strongest candidates for deep see pressure hulls. Research regarding composite cylinders, subjected to hydrostatic pressure, has been ongoing for a couple of decades, abroad, but domestic research is very new. Experimental investigations seem necessary, in order to understand their structural behavior not only up to the ultimate limit state, but in the post-ultimate regime. That experimental information will be very helpful in the development of any theoretical methods or to substantiate any commercial numerical packages for structural analyses. In this study, ultimate strength tests on seven composite cylinders subjected to hydrostatic pressure are reported, which includes the fabrication method of models, mechanical properties of the material, initial shape imperfection measurements, test procedure, and strain and axial shortening measurements during the tests. The ultimate strengths of the models were compared with predictions of numerical analyses. The numerical predictions are higher than the test results. It seems necessary to improve the accuracy of the numerical predictions by considering the initial shape and material imperfections.
Experimental Study on Development of Artificial Fishing Reefs Using Environment-Friendly Sulfur Concrete
Park, Sung-Bae ; Kim, Seok-Chel ; Kim, Kyoung-Hoon ; Hong, Chong-Hyun ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 58~64
New artificial fishing reefs are developed using modified sulfur concrete. Modified sulfur concrete, which is made of by-product aggregates and modified sulfur binder, has good properties, including high density, less water absorption, high strength, high salt resistance, and good affinity for living organisms. This paper shows the mechanical properties of modified sulfur concrete and its field tests under the sea. We have found that the pH-neutral materials attach microalgae and seaweed more readily, compared to the pH-high materials.
The Effect of Additive to Corrosion Resistance of Heavy Anti-Corrosive Paint
Moon, Kyung-Man ; Cho, Hwang-Rae ; Lee, Myung-Hoon ; Kim, Hyun-Myung ; Lee, In-Won ; Chun, Ho-Hwan ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 65~70
There are many kinds of protection methods for marine structures, with varyingeconomical and environmental advantages. The coating protection method is being widely used in both continental and marine structures. In this study, by adding some additives, such as Zn powder(Zn), carbon black(CB) to epoxy anti-corrosive paint, the effect on the corrosion resistance was investigated throughan electrochemical method. The additive of Zn(20)+CB(10) showed the lowest passivity current density. Polarization resistance in both cyclic voltammogram and impedance measurement of an additive of Zn(20)+CB(10) was also the largest value, compared to other additives. Furthermore, rusting and bubbling was not observed on the surface of the test specimen with the additive of Zn(20)+CB(10), compared to other specimens. It is suggested that the corrosion resistance of the anti-corrosive paint can be improved by using some additives.
The Welding Residual Stress and Fracture Toughness Characteristics of HT50 Laser Welded Joint
Ro, Chan-Seung ; Bang, Hee-Seon ; Bang, Han-Sur ; Oh, Chong-In ;
Journal of Ocean Engineering and Technology, volume 21, issue 3, 2007, Pages 71~76
Recently, many industries have been employing the application of laser beam welding, due to the resulting high welding quality, such as smaller width of melting and heat affective zone, smaller welding deformation, and fine grains of weldment, compared to arc welding. However, in order to appropriately utilize this welding process with steel structure, the characteristics of welding residual stresses and fracture toughness in welded joints are to be investigated for reliability. Therefore, in this study, the mechanical properties of weldments by arc and laser welding are investigated using FEM to confirm the weldability of laser welding to the general structural steel (HT50). The Charpy impact test and 3-points bending CTOD test are carried out in the range of temperatures between
, in order to understand the effect on the fracture toughness of weldments. From the research results, it has been found that the maximum residual stress appears at the center of plate thickness, and that the fracture toughness is influenced by strength mis-match.